Continuously operating cut off mechanisms



Dec. ll, 1934. K. SIEG CONTINuoUsLY OPERATING CUT-oFF MEGHANISM Filed June 5, 1935 4 Sheets-Sheet l INVENTOR N Km' zeg Q, M M am 7, ATTORNEYS Dec. 11, 1934. K. slEG' CONTINUOUSLY OPERATING GUT-OFF MECHANISM Filed June 5., 1935 4 Sheets-Sheet 2 QN n QQ IT 1J @w ww dl o o o o vwo GNN. i w mw o o QR o NK@ GNN N ww. w @we o im! ---n |Tl o o wm m@ l- -|-L ill l Q o w o @o o o ww n? f m Q uw LL Vw o o o 0%@ mm. Mm Q 4% S1 ..1 /z N |l| R L n T. u. w Si m :m Q-:orzo: o NIT E VL INVENTOR [fari/52@ BY. P/M HM 741A ATTORNEYS l dum Dec. 11, 1934. K. slEG 1,984,041

CONTINUOUSLY OPERATING GUT-OFF MECHANISM Filed June 5, 1953 4 sheets-sheet 5 y INVENTOR. [fa/' BY a d XW ATTORNEYS Dec. 11, 1934. K, 5|EG 1,984,041

CONTINUOUSLY OPERATING CUT-OFF -MECHANISM Filed June 5, 1953 4 SheetS-Sheet 4 ATTORNEYS Patented Dec. 11, 19,34 f.

UNITED STATES PATENT OFFICE CONTINUOUSLY OPERATING CUT OFF MECHANISMS ration of New Jersey Application June 5, 1933, Serial No. 674,811

19 Claims.

This invention relates to machines for cutting into sections continuously delivered sheet material, and more particularly to a control and driving mechanism for that type of cut-off mechanism in which the knives are in continuous movement, and in their cutting phases come together and then separate while traveling with the Inaterial.

For cutting comparatively stii material, such as double-faced corrugated board, it is important that the rate of travel of the cutting knives in the general direction of movement of the material at the time of cutting action, be substantially the same as the rate of travel of the material.

1f it is desired to maintain the feeding of the sheet material constant regardless of changes in the lengths of sections cut, then it is necessary to vary the total time of the cycle of movement of the cut-off mechanism, so that the frequency ci' operation of the knives will be inversely proportional to the lengths of sections cut. Each such change in the total time period of the cycle of the cut-oir mechanism changes the speed at the time of cutting, and requires readjustment of the relative rates of speed of the different parts of the cycles of the cutter, so as to again make the speed of the cutting knives, at the time of cutting action, correspond to the speed of the material.

One object of the present invention is to provide improved means for securing a travel of the cutterat the same speed as the sheet, even though the time period of the cycle of movement of the knife be varied to cut longer or shorter sections from the sheet traveling at any given speed.

Another object is to secure an increase in the range between the longest and shortest section which may be cut from a continuously advancing sheet by means of a continuously running cutter.

A further object is to permit very small adjustments to be made in the operation of the cut-ofi' mechanism, so that the sections cuil may be made to vary by very small increments.

In carrying out my invention, I employ a differential gearing between the drive and the cut-ofi mechanism, and I vary the speed of the cuttingv knives in their cycles of operation by varying the position of one or more of said gears.

As a feature of the invention, I provide a manually operable means for controlling the' range of movement of said movable gear or gears, so that said differential will operate to conform with the adjustment of the total cycle of frequency of operation of the cut-olf mechanism. The differential gearing may be used alone to effect the desired variations in the speed of the cutting knives, or,

if desired, may be used in conjunction with a pair of elliptical gears. By meansl of this arrangement, I am able to obtain a wider range of variation between the longest and shortest section. Also I may vary the speed of the cycle of operation of the cutting knife so that at any point in the cycle, the cutting knives may be almost at a standstill. This operation may be advantageous for cutting long sections.

Various other objects, advantages, and important features will be'hereinafter pointed out or will be apparent from a consideration of the speciflc construction illustrated in the accompanying drawings which constitute two of the many possible embodiments of the invention hereinafter claimed.

In these drawings:

Fig. 1 is a side elevation of the machine.

Fig. 2 is a horizontal section of the machine.

Figs. 3 and 4 are sections taken on the line 3-3 and 1 4 respectively of Fig. 2.

Fig. 5 is a somewhat diagrammatic showing of a part of the gearing shown in Fig. 3. y

Fig. 6 is a side elevation of a portion of another form of transmission between the drive and the cut-od mechanism.

Fig. 'l is an end view of the construction shown in Fig. 6, and

Fig. 8 is a section taken on the line 8 8 of Fig. 6.

In the traveling cut-off or ying shears illustrated there is employed a type of a pair of upstanding arms 10 pivoted at opposite sides of the machine on va transverse rock shaft or pair of pivot pins 11, and connected at their upper ends by a transverse beam 12 which carries the lower knife or cutting member 13. Each arm l0 carries a pivot pin 11 on which is mounted a lever 15, the two levers, at their upper front ends, carrying a transverse beam 16 on which is mounted the upper knife or cutter 17. The arms 10 extend substantially` vertically, so that the knife 13 swings back and forth substantially horizontally and approximately in the path of travel of the sheet.

The knives 13 and 17 are approximately the same distance from the pivot pins 1&1, so that as the levers 15 are operated; the knife 17 moves up and down, and cooperates with the lower knife to give a shear cut. For driving the knives and their carrying members, there is provided a transverse shaft having cranks 21 at opposite ends thereof, carrying crank pins 22 mounted in the ends of the levers 15. Thus, as the shaft 20 is rotated, the lower rear ends of the levers 15 are caused to travel in a circular path, and the front upper knife 17 travels in a substantially elliptical path. As the members which carry the two knives are connected by the pin 14, the rotation of the crank imparts a back and forth movement of `the lower knife in the direction of travel of the sheet. This` construction is illustrated and broadly claimed in my prior Patent 1,359,076.

The arms l0 may be forked adjacent to their upper ends so that said ends lie in planes at opposite sides of the arms l5. Thus the arms 15 lie in the same plane as the lower portions of the arms l0.

The sheet feeding mechanism comprises a pair of feed rollers 24 and 25, the lower feed roller 25 being driven from the main source of power. For instance, it may be provided with a gear 26 driven through a series of gears 28, 29 and 30 from the main drive shaft 27. The upper roller 24 may be freely rotatable or may be positively driven from the roller`25 by a train of gears as shown.

For driving the cut-off from the shaft 27 there is provided a train of gearing including means for selectively varying the frequency of operation of the cut-off mechanism. As shown a variable speed transmission 32 is driven by the drive shaft 27 and is of the ordinary type in which two pulleys, each including a pair of opposite conical discs, are provided, with a belt therebetween for transmitting power. The eifective diameter of the pulleys may be altered by moving the conical discs of one or both pairs toward and from each other. The details of this mechanism are not shown as it may be of any standard design, such as that known in the trade as the P. ll. V. or the Reeves drive, or may constitute a speed change device of the gear type.

As an important feature of the present invention, the drive connection between the variable transmission 32 and the operating shaft 20 of the cut-off mechanism includes a differential gearing which is so automatically operated during each cycle of operation of said mechanism as to vary the speed ratio of said gearing and consequently vary the relative rates of speed of the eut-off mechanism in its cycle. By differential gearing I mean a gearing in which one of the gears is bodily movable to change the speed ratio of the gearing. This differential gearing is driven by a pinion 58 on the output shaft 33 of the variable speed transmission 32 and meshing with the spur gear 59 mounted on a counter shaft 66. The shaft 60 has a spur gear 61 which meshes with the external teeth of an annular gear 62 carried on a sleeve 63 supported by suitable bearings on a shaft 56 so that said gear 62 will be rotatable with respect to said shaft 56. The shaft 56 has secured thereto a gear 6d concentric with the gear 62 and driven from the annular gear 62 by one or more differential pinions 65 meshing with said gear 64 and the internal teeth of the annular gear 62. Three of such differential pinions are shown spaced 120 apart to effect a balanced arrangement. By means of this train of circular gears, when the axes of the differential pinions 65 are stationary, the speed ratio between the shafts 56 and 33 will be constant. The shaft 56 drives the crank shaft 20 of the cutter through a pair of elliptical gears 100, 101.

In case the elliptical gears are not employed, a single shaft may be used in place of the shafts 20 and 56, That is, the shaft 56 may be the crank shaft or the differential may be on the shaft 20. If a rotary type of cut-off be used, the shaft 20 will not be a crank shaft. and one of the cutters may be on the shaft 20 or an extension thereof, or on an extension of the shaft 56.

Means are provided for oscillating the differential pinions 65 bodily during each cycle of operation of the cut-off mechanism, in order to vary the speed ratio between the drive shaft 33 and the shaft 56. For that purpose, the differential pinlons 65 are journaled to .a ange 66 of a sleeve 67 which encircles the shaft 56, and which is supported thereon for rotation with respect thereto by suitable bearings.

In the form shown in Figs. l to 5, this sleeve 67 is oscillated by linkage means driven from the shaft 60. This includes an arm 68 having one end connected to said sleeve and theother end pivoted to one end of a connecting rod or link 70. The intermediate portion of the link'70 is pivotally connected to one end of a link 71, the other end of said link 71 being pivotally connected to a crank on a crank arm 69 secured to the shaft 60. As the shaft 60 rotates, it will operate the linkage between this shaft and the sleeve 67 and thereby oscillate the differential pinions 65 bodily.

The variation in operation of the differential gearing is effected by permitting controlled movement of the other end of the link 70. For that purpose, said end of the link 70 is pivoted to a block 73 slidably mounted on a guide 72. As the shaft 60 rotates, the link raises and lowers and at the same time moves endwise. rZf'he block 73 slides in the guide 72 and serves to limit the movement of the link 70 so that the angle of oscillation of the arm 66 is correspondingly limited.

By varying the position of the guide the movement of the link 70 may be such that for any frequency of operation of the cut-ofi, the dierential will cause the knives to travel at the same speed as the traveling material at the instant of cutting.

In the specific form shown, the guide 72 is angularly adjusted to effect this control. It extends diametrically of a normally stationary member 74 preferably in the form of a worm wheel meshing with a worm 75 which may be rotated to bring the guide 72 at any desired angle in respect to the general direction of the length of the link 70. The worm wheel is supported in. a housing 74a having bearing surfaces 74h engaging annular shoulders formed at the ends of said worm wheel.

The variable speed transmission 32 is adjustable to e'ect changes in the frequency of operation of the cut-off in respect to the speed of travel of the sheet, and the guide 72 Vmay be adjusted to make the speed of travel of the cutter, when cutting, substantially the same as the speed of the sheet. As one important feature of the invention there is provided a single member for controlling both the variable speed transmission and the differential gearing, so that when adjusting to give any desired length of cut-off section, the speed of the knives in their cycle will be correspondingly adjusted.

Such a single control member is shown as a control shaft 41. As shown it drives a counter shaft aia through a, pair of gears 41o, and the counter shaft 41a has a sprocket Wheel 42 which serves, through a chain 42a, to drive a sprocket wheel 43 on the speed ratio control shaft i4 of the variable speed transmission 32. The rotation of this shaft 44 eiects a change in the speed rati.,` 'A

between the output shaft 33 and the input shafi 27 to selectively vary the frequency of operation of the cut-off in accordance with the length of section desired. For rotating the shaft 4l there is provided a spindle 35 carrying a hand wheel 36 at oneend thereof and a sprocket wheel 37 at the other end thereof. Through a chain 38, this sprocket 37 drives a sprocket wheel 40 connected to the control shaft 41.

In order that the operator may move the control hand wheel 36 the proper extent to give any desired length of section, there is provided a calibrated indicating mechanism. This mechanism includes a fixed stud 46 supported on a bracket 45 and. loosely carrying a dial gear 47 having a hub 48 which cooperates with a braking mechanism 49 by means of which the position of said dial gear may be set at any fixed point. Secured to said dial gear 47 is an indicating dial 50, the rim of which carries a series of section length graduations indicatively cooperating with a pointer (not shown). Meshing with the dial gear 47 is a pinion 51 connected to the control shaft 41.

In the connection between the control shaft 41 and the worm 75, compensating means must be provided so that the Worm wheel 74 is rotated a proper amount to give the proper effect for each change in the speed ratio of the variable speed transmission. For that purpose, the worm 75 is 4driven from the shaft 41 through a pair of intersuitable means, as for instance by a. chain 78 passing around the sprocket 79 on the shaft of said cam gear, and around a sprocket 80 connected to the control shaft 41. For rotating the worm 75 from the cam gear 76 the shaft of said gear has connected thereto a gear 81 meshing with a gear 82 connected to the shaft of the worm 75.

The rotation of the worm 75 causes a corresponding yrotation of the worm Wheel 74, and changes the angular position of the guide 72. This adjustment causes a corresponding change in the movement of the free end of the link 70, so that the movement transmitted to the arm 68 is correspondingly modified. Both adjustments in the variable speed transmission and the differential gearing may be made Whilethe machine is running. The worm wheel 74 is locked by the worm 75 in adjusted position.

In Figs. 6 to 8 there is shown another form of link mechanism for bodily oscillating the differential lpinions 65 during one cycle of operation of the cut-off mechanism. In this form, there is provided an arm or yoke 83 connected intermediate its ends to a rock shaft 84 suitably journaled. This arm 83 is oscillated about the axis of the shaft 84 by means of a link 85 pivotally connected at one end to the outer end of the crank arm 69 and at the other end to a bracket 86 extending from said arm 83. The oscillatory movement of the arm 83 effected through the operation of the shaft 60, is transmitted to the arm 68 by means of a link 87 pivotally connected at one end to the outer end of the arm' 68 and having the other end thereof pivotally connected to a block 88 supported on the arm 83. The latter end of the link 87 is advantageously bifurcated and has the spaced prongs thereof disposed on opposite sides of the arm 83 and connected to a pivot pin 89. The rockshaft 84 is connected to the arm 83 by means of a bracket 90 extending from a flange 91 at one end of the rock shaft 84 and spaced from the prongs of the link 87 to permit free movement of said link.

The extent of angular oscillation of the arm 68 depends on the position of the block 88 from the axis of the rock shaft 84. In the position shown in Figs. 7 and 8, the link 87 is in neutral position with the block 88 in axial alignment with the rock shaft 84, so that the oscillatory movement of the arm 83 is not transmitted to the link 87.

In order to selectively movethe block 88 in adjusted position so as to obtain the desired movement of the arm 68, the arm 83 is provided with a pair of spaced parallel guides 95, the block 88 being mounted for slidable movement along said,

guides. Extending longitudinally between these guides 95 and having a threaded engagement with the block 88 is a screw 96, the rotation of which causes the movement of the block 88 along the guides 95 into selective positions away from the axis of the rock shaft 84. This rotation of the screw 96 may be effected from the control shaft 41, or may be effected through an independent control. In the specific form shown, this sc'rew 96 is independently controlled by means of `a hand wheel 97 connected to one end'of the screw. The guides 95 may be provided with a series of calibrations which cooperate with markings on the block 88 so that adjustments may be made to conform withl the adjustments in the variable speed transmission 32.

The differential gearing and the linkage for varying the speed ratio thereof may be so constructed as to obtain the desired speed variation in the cycle of operation of the cut-off mechanism without any additional speed varying device. However, from a standpoint of efficient design the guides 72, in the form shown in Figs. 1-5, and

the guides 95, in the form shown in Figs. 6-8 are not intended to give the full range of adjustment in the form shown as they may be supplemented by the pair of intermeshing elliptical gears 100 and 101 in the transmission between the drive and the cut-off mechanism.

The elliptical gears 100 and 101 and the differential gearing operate in series, the elliptical gears being fixed with respect to the drive, and both the elliptical gears and the differential gearing combining to drive the cutter at a speed varying in the cycle of operation of the cut-off mechanism, so that the speed of the latter at the instant of cutting Will be maintained substantially the same as that of the sheet for any given speed of sheet irrespective of the lengths of the sections into which the sheet is cut.

The gear v'wheels of the differential gearing are advantageously so proportioned that the shafts r 60 and 56 will rotate at the same angular velocity when the axes of the differential pinions 65 are stationary. For instance, the gear 61 has a pitch diameter one-half the external pitch diameter of the annular gear 62, and the gear 64 has a pitch diameter one-half the internal pitch diameter of said annular gear.

When the arm 68 is moving in the same angular direction as the annular gear 62, the speed of the gear 64 is less than its normal speed, and when the arm is moving in the opposite direction the yspeed of the gear 64 is greater than its normal speed. The rate of speed variation of the gear 64 depends upon the angular velocity of the arm 68.

For adjusting the operation ofthe linkage in order to change the relative rates of speeds in the cycle of operation of the cut-off mechanismto conform withthe change in frequency of operation of the cut-off, I may employ means independent of that which controls the frequency of operation of the cut-off mechanism. In other words, there may be two independent control members.

Having thus described my invention, what I iii claim as new and desire to secure by Letters Patcnt is:-

1. An apparatus for subdividlng continuously advancing sheet material transversely into sections, including a cut-od mechanism movable substantially in the same direction as the material at the instant of cutting, a differential gearing for imparting continuous movement to said cut-ofi mechanism, means for automatically operating said gearing during each successive cycle of operation of said cut-off mechanism for varying the speed ratio of said differential gearing during each of said cycles, and means operable while the machine is running for adjusting said operating means to modify the variation in speed ratio of said differential gearing during each of said cycles.

2. An apparatus for subdividing continuously advancing sheet material transversely intosections, including a cut-ofimechanism, a dierential gearing for operating said cut-H mechanism, means for automatically' operating said diiferential gearing during each successive cycle of operation of said cut-off mechanism for varying the speed ratio of said gearing during each oi' said cycles, adjustable means for varying the freduency of operation of the cut-oi mechanism to vary the length of sections being cut, and means automatically operable upon the adjustment of said last mentioned means for adiusting said first mentioned means to modify the variation in speed ratio of said differential gearing during each cycle of operation of said cut-cid mechanism in accordance with the change ir requency of operation of said cut-ofi mechanism,

3. An apparatus for subdividing continuously advancing sheet :material transversely into sections, including a cut-off Ymechanism movable substantially in the same direction as the material at the instant of cutting, a drive shaft, a driving connection between said shaft and said cut-od mechanism, and including a 'variable speed transmission for varying the frequency of operation of said cut-oil mechanism in accordance with the length of the sections desired, a diderential gearing, and means for operating said differential gearing during each successive cycle of operation of said cut-off mechanism for varying the speed ratio of said gearing during each of said cycles, means for adjusting said variable speed transmission for determining the length of the sections while the apparatus is running, and means adjusting said differential gearing to modify de variation in speed ratio of said gearr each cycle of operation of said cut-o a whiie the apparatus is running so as to maintain` the speed of travel of said cut-ofi mechanism substantially the same as 'that of the material at the instant of cutting operation.

e. An apparatus for subdi iding continuously advancing sheet material transversely into sections, including a cut-off mechanism movable in the same direction as the material at the instant of cutting, a shaft, a power transmitting mechanism between said shaft and said cut-ofi' mechanism for imparting continuous movement to said cut-off mechanism, `a drive shaft substantially parallel to said rst shaft, a differential gearing between said shafts, and' means automatically operated from said drive shaft during each cycle of operation of said cut-off mechanism for bodily oscillating one or more of the gears of said gearing for varying the speed ratios between said drive shaft and said cut-Gif mechanism during each of said cycles.

Lose 5. An apparatus for subdividing continuously advancing sheet material transversely into scctions, including a cut-o mechanism movable in the same direction as the material at the instant of cutting, a shaft, a power transmitting mechanism between said shaft and said cut-ofi mech-i anism for imparting continuous movement to said cut-ofi mechanism, a drivingshaft transversely spaced from said first mentioned shaft, a differential gearing between said shafts, a crank. connected to said driving shaft, and means operated, from said crank for bodily oscillating one of the gears of said gearing to vary the speed ratio bca tween said shafts. i l

d. in combination, a cut-a mechanism. ldriving means therefor, including a differential gearing, and means including a linkage for automatically operating said diiferential gearingduijing each cycle of operation of said cut-.oif mechanism for varying the' speed ratio of said gearing, and means for adjusting said linkage while the machine is running to vary the speed ratio of said gearing during each cycle of operation of said cut-orf mechanism.

7. ln combination, a cut-*0H mechanism, `driv-` ing means therefor, including a drive shafta driven shaft, a differentital gearing between said shafts, and a linkage between said drive, shaft and one of the gears of said gearing for oscillating said gear bodily from said drive shaft during each cycle oi operation of said cut-ofi mechanism, a guide for a portion of said linkage along which said portion slides during each cycleoi operation of said differential gearing, andrneans for cha sing the position of said guide toeffect adiustments in the operation or said linkage,

E. In combination, a cut-ofi mechanism, driving means therefor, including a drive shaft, a driven shaft, a diiferential gearing vbetweensaid shafts, and a linkage between said drive shaft and. one of the gears of said gearing for. oscillating said gearing bodily from said drive ,shaft during each cycle of operation o said ,cut-off, mechanism, a rotatable member, a guide'm lsaid rotatable member for a portion. of saidlinllrage whereby said portion slides along said guide during each cycle of operation of said linkage, and means for rotating said member to change the angular position of said guide, whereby the operof said linkage is modified. i, I

9. lin combination, a cut-off mechanism, .drive ing means therefor, including a shaft, a driven shaft, a differential gearing betweensaid shafts, linkage between said drive shaft vand one of the gears of said gearing for oscillating said gearing bodily from said drive shaft during each cycle of operation of said cut-off mechanism, a gear wheel, a guide mounted diametrically on said gear wheel for a portion of said linkage, and an irreversible gearing for rotating said 'gear wheel to effect angular adjustments in the position of said guide, and for locking said gear wheel in adjusted position.

lil. .in combination, a cut-ofi` mechanism, driving means therefor, including a drive shaft, a driven shaft, a differential gearing between said shafts, and a linkage between said drive shaft and one of the gears of said gearing for oscillating said gearing bodily from said drive shaft during each cycle of operation of said cut-oi mechanism, and including a rock shaft, an arm connected to said rock shaft, said arm being provided with a guide, a link having a portion thereof in said guide, and means for oscillating rsaid* CTI arm from one of said shafts to cause corresponding movement of said link.

11. In combination, a cut-olf mechanism, driving means therefor, including a drive shaft, a driven shaft, a differential gearing between said shafts, a linkage between said drive shaft and one of the gears of said gearing for oscillating said gearing bodily from said drive shaft during each cycle of operation of said cut-off mechanism, and including a rock shaft, an arm connected to said rock shaft, said arm being provided with a guide, a link having a portion thereof in said guide, and means for adjusting the position of said link in said guide to modify the operation of said link.

12. In combination, means for feeding a continuous sheet of material at substantially constant speed, a cut-off mechanism for subdividing the sheet into sections, including a crank shaft, a member mounted to move back and-forth in the same path substantially parallel to the direction .of feeding movement of the material to be cut, a second member pivotally connected to the first mentioned member and to the crank of said crank shaft, a pair of cooperating cutters carried by said members, a drive shaft, a power transmitting mechanism between said drive shaft and said crank shaft, and including a differential gearing, means for automatically bodily moving one gear of said differential gearing during each cycle of operation of said cutters to vary the speed ratio of said differential gearing during each of said cycles, and means operable while the machine is running for varying the extent of said bodily movement.

13. In combination, means for feeding a continuous sheet of material at substantially constant speed, a cut-off mechanism for subdividing the sheet into sections, including a crank shaft, a member mounted to move back and forth in the same path substantially parallel to the direction of feeding movement of the material to be cut, a second member pivotally connected to the irst mentioned member and to the crank of said crank shaft, a pair of cooperating cutters carried by said members, a drive shaft, a power transmission mechanism between said drive shaft and said crank shaft for continuously rotating said crank shaft, and including a differential gearing, means for automatically bodily moving one gear of said differential gearing during each cycle of operation of said cutters to vary the speed ratio of said differential gearing during each of said cycles, and means operable while the machine is running for varying the extent of said bodily movement.

14. A machine for subdividing material into sections, including means for advancing av continuous sheet of material at a substantially uniform speed, a pair of cutters movable back and forth in the general direction of the travel of the material, a crank shaft for operating said cutters, a drive shaft, a power transmitting mechanism between said drive shaft and said crank shaft, and including a differential gearing, means for automatically bodily moving one gear of said differential gearing during each cycle of operation of said cutters for varying the speed ratio of said differential gearing during each of said cycles, and means operable while the machine is running for varying the extent of said bodily movement.

15. A machine for subdividing material into sections, including means for advancing a continuous sheet of material at a substantially uniform speed, a pair of cutters movable back and differential gearing during each of said cycles,

and means operable while the machine is running for varying the extent of said bodily movement.

16. An apparatus for subdividing continuously advancing sheet material transversely into sections,` including means for advancing said material at a substantially uniform speed, a cut-off mechanism movable substantially in the same direction as the material at the instant of cutting, a pair of intermeshing elliptical gears for driving said cut-off and varying the speed thereof in its cycle, a differential gearing for driving one of said elliptical gears, and means for automatically operating said differential gearing during each cycle of operation of said cut-off mechanism for modifying the speed variation imparted to said cut-olf by said elliptical gears.

17. An apparatus for subdividing continuously advancing sheet material transversely into sections, including means for advancing said material at a substantially uniform speed, a cut-olf mechanism movable substantially in the same direction as the material at the instant of cutting, a pair of intermeshing elliptical gears for driving said cut-off and varying the speed thereof in its cycle, a train of circular gears in series with said elliptical gears, and means for bodily moving one gear of said train of gears back and forth during each cycle of operation of said cut-olf mechanism for modifying the speed variation imparted to the cut-off mechanism by said elliptical gears.

18. An apparatus for subdividing continuously advancing sheet material transversely into sections, including means for advancing said material at a substantially uniform. speed, a cut-off mechanism movable substantially in the same direction as the material at the instant of cutting, a pair of intermeshing elliptical gears for driving said cut-olf and varying the speed thereof in its cycle, a train of circular gears in series with said elliptical gears, means for bodily moving one gear of said train of .gears back and forth during each cycle of operation of said cut-olf mechanism for modifying the speed variation imparted to the cut-off mechanism by said elliptical gears, and means manually operable while the machine is running for varying the extent of said back and forth movement.

19. An apparatus for subdividing a continuous web of sti sheet material transversely into sections, including feeding means for continuously delivering said web, a cut-off mechanism movable at'the instant of cutting in substantially the same direction as said web, a drive shaft, driving connections between said shaft and said feeding means for operating the latter at a substantially uniform speed, and driving connections between said shaft and said cut-off mechanism for imparting a continuous 'movement to the latter, said last mentioned connections including a variable speed transmission for varying the average or mean speed of said cut-off mechanism in its cycle, and thereby varying the cutting operation of said cut-oi mechanism in accordance with the length of section desired, and means for varying weiem transmission being adjustable WhileV the emma ratas is ci@ e, im' venin@ the length. of the euzof eecmons amd mem'emm the speed of the cmw mechemsm ai; c ci cutting smcstantmy 'mel seme es el? @he Cia 

